The present invention relates to a method and equipment for coupling a membrane to the skin of a human being, and particularly the invention relates to coupling equipment to a human being for purposes of transmission of shock waves or the like.
Medical diagnoses and therapy using particular equipment, often requires that, in a mechanical sense, that equipment is to be coupled to the body of the patient. Specifically, a transmission path is to be established between the body of the human being/patient and the equipment. This transmission may involve, for example, radiation, or mechanical waves, to be transmitted from the equipment into the body of the patient, without incurring losses generally, and without unduly and unforeseeably varying the transmission path of these waves or radiation. Equipment of the type to which the invention pertains relates, for example, to lithotripsy, but can be used in other equipment as well.
In preparation of coupling such equipment to the body of a human being, it is customary to remove body hair from the skin, so as to avoid immediate and direct interference by the hair of the skin upon the equipment and the coupling to be effected. In addition, a certain gel or pasty material is placed upon the skin of the body such that any physical equipment, such as a membrane, an electrode, or the like, will, in fact, uniformly contact this particular coupling material. On the other hand, this coupling material gaplessly abuts and adheres to the body and the skin of the patient. This paste, in other words, has as its primary function, the removal of any transmission path uncertainty between equipment, on one hand, and the skin of the human being, on the other hand. One is no longer dependent upon a clearly uniform gapless abutment of equipment itself and the skin of the patient. The interpositioning of a paste removes so to speak any inherent irregularity that may present itself, if an immediate and direct "dry" contact were effected.
A problem has been observed in a sense that upon applying this paste to the skin of the human patient and then attaching the equipment to that paste, there still is the possibility that air bubbles get trapped, and, therefore, provide for a certain local non-uniformity. Clearly, medical technical personnel or physicians may acquire personal skills sufficient to avoid irregularities on that account, and particularly they may well be aware of the strict avoidance of any manipulation that may result in the inclusion of such air bubbles. On the other hand, it is immediately apparent that the avoidance of the inclusion of air bubbles in the transmission path between equipment and the patient does become a matter of personal skill but also personal, i.e., subjective judgment. This may well be satisfactory in many instances but it is obvious on its face that it is easy to conceive instances in which this kind of a reliance is no longer justified.
It has, therefore, been suggested to provide, as an additional step for an evacuation procedure of any space between the skin of the patient on one hand, and a membrane for coupling, on the other hand. While basically satisfactory and particularly satisfactory in principle, it simply was found as a matter of practice that isolated air bubbles still remain trapped "somehow".
In the field of contactless lithtropsy, i.e. the contactless comminution of concrements in the body of a human being, the foregoing problem has been avoided in the past entirely by simply placing the patient into a tub filled with water, and there is an immediate and interface free transmission path provided between the liquid as it flushes around the body of the patient, on one hand, and a source of shock waves, on the other hand. The source of shock waves is simply in immediate and direct contact with that coupling fluid, so that there is no danger of interference on account of any physical, mechanical interface within the system and providing some kind of barrier between the shock wave generation and the skin of the patent, on the other hand. However, the utilization of such a tub is not too satisfactory.